This invention relates to a digital still camera, and in particular to a digital still camera using a memory card as a recording medium, said memory card being mounted to the camera body in a manner such that it is capable of mounting and demounting.
In recent years, it has been put to practical use a still camera which has such a structure as to make the optical image of a subject focus onto a solid state image sensor such as a CCD through an optical imaging system such as a photographing lens, a stop, and so forth, and to convert the outputted electrical image signal which has been photoelectrically converted by the image sensor into digital data, said digital image data being recorded in a semiconductor memory comprised in a memory card which is mounted to the camera body in such a way that it is capable of mounting and demounting.
However, in case of the memory card for recording the image signal being capable of mounting and demounting to the camera body as mentioned above, there has been a possibility for the memory card to be demounted inadvertently by the user even while the memory card is being accessed.
The aforesaid access to the memory card is done with the processes such as recording of the photographed image, reading of the recorded image data, processing of the recorded image data, and so forth. Accordingly, there is a possibility for the memory card to be demounted during such processes, and in pariticular, in case of using a flash memory for the simiconductor memory, it is required to erase null data so as to make a free area, and besides it requires a comparatively long time to erase said null data, hence there has been a problem that the possibility for the memory card to be demounted inadvertently during such erasing process of the null data as mentioned above.
This invention is made in view of the above-mentioned problem, and the object of it is to provide a digital still camera capable of avoiding the inadvertent demounting of the memory card during the access to it.
For that purpose, according to the following structure in the first mode of practice of the invention, the digital still camera, which has a structure such that a memory card comprising a memory capable of mounting and demounting is mounted to the camera body and the optical image of a subject is converted to an electrical image signal to record it in said memory, is provided with a means for detecting the operational state preceding the demounting of said memory card out of the camera body, and a warning means for giving a warning on the occasion of detecting said operational state by said detecting means during the access to said memory card.
By the structure as mentioned above, it is detected that the memory card is going to be demounted and if it happens during the access to the memory card, the warning is given not to carry out the demounting operation because the memory card is in the state of accessing to it, and accordingly it is prevented that the operation is continued to demount the memory card.
The operational state preceding the demounting of the memory card as stated herein means the operational state in any step before undoing the electrical connection between the memory card and the camera body in the operational procedure. Further, it is desirable to use an LED or a buzzer for the warning means, but a letter display of an warning sentence may well be used, that is, any means that can inform the user of the requirement not to demount the memory card will do.
On the other hand, according to the following structure in the second mode of practice of the invention, the digital still camera, which has a structure such that a memory card comprising a memory capable of mounting and demounting is mounted to the camera body and the optical image of a subject is converted to an electrical image signal to record it in said memory, is provided with a means for detecting the operational state preceding the demounting of said memory card out of the camera body, and a mechanical locking means to make it unable for the memory card to be demounted by mechanically locking said memory card to the camera body on the occasion of detecting said operational state by said detecting means during the access to said memory card.
By the structure as mentioned above, when it is detected that the memory card is going to be demounted and if it happens during the access to the memory card, the memory card is mechanically locked to the camera body so as not to be demounted by the user in order to prevent that the operation is continued to demount the memory card.
In other words, the aforesaid locking means does not lock the memory card so long as the demounting operation is not carried out even during the accessing to the memory card, however, it forces the memory card to be locked to make it unable to be demounted if the demounting operation is attempted during the accessing.
In the following structure according to the third mode of the invention, the digital still camera is further provided with the warning means for giving the warning that the memory card is unable to be demounted by the aforesaid locking means.
By the struture as mentioned above, the user can be informed that the state of being unable to be demounted for the memory card is due to the action of the locking means for preventing the demounting of the memory card during the access. In this case too, an LED or a buzzer should deseirably be used for the warning means.
According to the following structure in the forth mode of practice of the invention, the digital still camera is comprised of a mounting portion of the aforesaid memory card provided at the aforesaid camera body, the mounting portion covered by a card cover, and the aforesaid demounting detecting means detects the opening of said card cover as the operational state preceding the demounting of said memory card out of the camera body.
In the structure as mentioned above, it may happen with a good possibility that the memory card will be demounted next when the aforesaid card cover is opened because the opening of the aforesaid card cover is the precondition of the demounting of the memory card. Therefore, when the card cover is opened and if it happens during the access to the memory card, the carrying out of the demounting of the memory card following the opening of the card cover is prevented by giving a warning or locking the memory card to make it unable to be demounted.
However, the operational state preceding the demounting of the memory card is not limited to the above-mentioned opening of the card cover, and for example, it will also do to detect touching the eject button or the lock-releasing button (or that the operation has been carried out to the step immediately before demounting is actually made). In other words, any operational state will do before the step of electrical disconnection among a series of demounting operations for the memory card, and it is favorable that detecting the earlier operational state than the last one of the two or more required operations of different kind for the demounting (the opening of the card cover and the drawing out of the memory card, for example).
According to the following structure in the fifth mode of practice of the invention, the digital still camera has a structure such that the aforesaid operational state is detected by the aforesaid demounting detecting means during the accessing to the aforesaid memory card, and if the accessing process can be serially in time divided into plural process units, an access-discontinuing means is provided for discontinuing the process at the time of finishing the unit in processing.
By the structure as mentioned above, if the content of the processing can be divided in time series, it is not required to wait until all the process units is finished for avoiding the demounting of the memory card due to the waring or locking, but it is made to be allowed earlier to demount the memory card at the step of finishing the process unit in processing.
According to the following structure in the sixth mode of practice of the invention, the digital still camera has a structure such that the aforesaid memory comprised in the memory card is a flash memory, having such structure that the control process is carried out in unit-by-unit manner for the predetermined erasing block units, said control process producing free area by erasing only the null data made on the occasion of rewriting the data, and when the aforesaid operational state is detected by the aforesaid demounting detecting means during the aforesaid access for erasing, the erasing process is discontinued at the time of finishing the erasing of the erasing block unit in processing.
By the structure as mentioned above, if the operation of demounting of the memory card is attempted during the erasing process of the null data, it is not required to wait until the erasing process for all the erasing block units is finished for avoiding the demounting of the memory card, but it is made to be allowed to demount the memory card at the step of finishing the erasing of the erasing block unit in processing at that time, while the erasing block units which have not been erased remain as unerased.
By the structure as set forth in the first mode of practice of the invention, such effect is obtained that when the operation to demount the memory card is going to be carried out during the access, the warning is given to inform the user that the memory card is in the process of accessing, hence it can be avoided that the user will inadvertently demount the memory card.
By the structure as set forth in the second mode of practice of the invention, such effect is obtained that when the operation to demount the memory card is going to be carried out during the access, the memory card is forced to be locked to enter in the state of being unable to be demounted even if the user tries to demount it, hence it can be securely prevented that the memory card is demounted during the access to it.
By the structure as set forth in the third mode of practice of the invention, such effect is obtained that when the memory card is going to be demounted, the memory card is locked and at the same time the warning is given to inform the user that locking is made because the memory card is in the process of accessing, hence the user can be realized that the memory card is locked because of the attempt to demount it during the access.
By the structure as set forth in the fourth mode of practice of the invention, such effect is obtained that when there is some possibility of making the demounting operation upon opening the card cover covering the memory card mounting portion, it is prevented that the memory card in the process of accessing is demounted following the opening operation of the card cover, by warning the user of the memory in accessing, or locking the memory card.
By the structure as set forth in the fifth mode of practice of the invention, such effect is obtained that by discontinuing the accessing process, the state of being capable of demounting the memory card can be made to be recovered in a short time after the demounting operation is about to be done.
By the structure as set forth in the sixth mode of practice of the invention, such effect is obtained that the demounting operation of the memory card is not hindered for a comparatively long time until the erasing of all the null data in the flash memory is finished, but the demounting of the memory card can be allowed in a short time.